If it was the people actually investing in AI all saying it's a bubble, implying that they are holding back, not all-in, for fear of it crashing, then it'd have room to run further (until they were all-in, and leveraged to the eyeballs, cf subprime housing crash liar loans, dot-com crash investor margin accounts).

However, it seems more like the people pumping billions into AI are all still "this is going to the moon" gung-ho, and unless they are investing billions of CASH, then I guess they are borrowing to do so.

I don't know how this financing works - maybe no fear of having it pulled like a foreclosure on a subprime mortgage holder, or a broker margin call, but it's not going to end well if these investments start to fail and the investors start running for the door.

Peter Thiel's recent exit from NVidia should be a bit concerning given his good record on macro bets and timing.